﻿<!DOCTYPE html>
<html>
	<meta charset="UTF-8"/>
	<head>
		<script>
			//逻辑运算符
			//var 是不是男神 = 帅 && 有钱 && 智商高 && !gay;
			
			//var 是不是男神 = 帅 || 有钱;
			
			var num = 100;
			var a1 =  num > 20 && !(num > 200);
			//alert(a1);
			
			
			//被4整除，非整百年  或者  被400整除
			var year = 1900;
			var isRN = year%4==0 && year%100!=0 || year%400==0;
			
			document.write(isRunNian);
			
			
			//关键字var\typeof\true\false
			//保留字int\class\go to
			
			//变量名称的原则 
			//1 不可以数字开头
			//2 只能使用数字、字母、下划线、$
			//3 变量名称要做到见名知意
			/*
			var username = "yt";
			var schoolname = "";
			var age = 20;
			var sex = 
			var width = 
			var height = 
			var weight = 
			*/
		</script>
	</head>
	<body>
		
	</body>
</html>











